Where the figures come from

The figures given in the league tables are the result of a new approach to
measuring maternal mortality  notoriously difficult to estimate because of
both under reporting and misclassifying of deaths.

The new approach, developed by Johns Hopkins University, WHO and UNICEF,
uses all available information including vital registration data, household
surveys, sisterhood surveys (which ask women about the pregnancies and deaths of
their sisters), and reproductive-age mortality surveys. To compensate for under
reporting and misclassification, or for the non-availability of data in some
countries, the new estimates also make use of a mathematical model based on two
key independent variables  the general fertility rate and the proportion
of births attended by a trained person.

Despite data limitations, these revised estimates represent a major
improvement on early efforts to quantify maternal mortality for all nations.

The country-by-country estimates given here differ, in some cases
considerably, from previously estimated national statistics.

The new figures apply to the early 1990s. As a different estimating
technique has been used, these figures should not be used for comparison with
previous estimates in order to establish trends.